Meryl Streep's daughter Mamie Gummer is comforted by Patrick Kennedy, who
appears in 'Downton Abbey', after the demise of her marriage to Benjamin
Walker.

As the swindler Terence Sampson in Downton Abbey, Patrick Kennedy had a nasty impact on the Earl of Grantham. In real life, the dashing Old Harrovian had no need of card tricks to impress Mamie Gummer, the daughter of Meryl Streep.

Mandrake hears that Kennedy, 36, has been comforting Gummer after the collapse of her marriage to Benjamin Walker, 31, the American actor and stand-up comedian. “They have become very close,” says one of Kennedy’s friends.

An old school chum of Benedict Cumberbatch, Kennedy made his first public appearance with Gummer at the first night of a Broadway revival of The Winslow Boy, Sir Terence Rattigan’s play, last week. He and Gummer have been working together on the American television drama The Money, about a ruthless media mogul.

Mamie, 30, who is one of Streep’s four children with her husband, the sculptor Don Gummer, announced in March that she had separated from Walker, whom she married two years ago on her parents’ estate in Connecticut. They met while co-starring in a Broadway production of Les Liaisons Dangereuses.

Julian Fellowes, the creator of Downton Abbey, was impressed by the actor. “I am happy to speak up for Patrick Kennedy,” he tells me. “I thought he was excellent. Patrick proved extremely skilful at taking responsibility for his own story. He also injected a quality of sympathy into a character who was not tremendously sympathetic at first glance, for one reason or another.”

At Harrow, Kennedy played the son Biff to Cumberbatch’s Willy in a school production of Death of a Salesman. They went on to appear together opposite Keira Knightley in the film Atonement, in the BBC drama Parade’s End, and in Steven Spielberg’s big-screen adaptation of War Horse.

“Steven was saying, 'My God, you guys, you are like a club, you’re so unbelievably perfect for this, it’s great,’ ” Kennedy said. “But we are really vehicles for the horses, it’s their journey.”